In a August 8th 2017 article at the Institute of Electrical and
Electronics Engineers (IEEE) Spectrum Magazine website,
Evan Ackerman reports on JPL's design for the "Automaton Rover for
Extreme Environments" (AREE).

The problem for robots in extreme environments such as the surface
of Venus is that the electronics is subjected to extreme heat.
In the case of Venus, 464 °C.

The Soviet Venera probes lasted only a couple of hours. Their electronics
were encapsulated in a hermetically sealed titanium pressure vessel.

The team of engineers behind AREE have been experimenting with
substituting many of the electrical and electronic components for
mechanical counterparts in an attempt to increase system reliability.

Quote:

Originally Posted by Evan Ackerman, IEEE Spectrum

With funding from the NASA Innovative Advanced Concepts (NIAC) program, the JPL team wants to see whether it might be possible to build a Venus exploration rover without conventional sensors, computers, or power systems. The Automaton Rover for Extreme Environments (AREE) would use clockwork gears and springs and other mechanisms to provide the majority of the rover’s functionality, including power generation, power storage, sensing, locomotion, and even communication: no electronics required. Bring on the heat.

Quote:

Originally Posted by Jonathan Sauder, JPL

We started out in our NIAC Phase I proposal thinking that we were going to build a fully mechanical rover architecture that would not use any electrical subsystems or electronics at all, replacing all the standard electrical subsystems with mechanical computing. As we started to dig into it more, we realized that you can’t build a traditional Mars Curiosity-style rover with a centralized core processor ... Instead, what we’ve had to do is focus on something that gives more of a distributed architecture, where we have many simple mechanisms around the device, guiding it, signaling it, telling it where to go.

Originally we were going to try to do a number of our scientific measurements mechanically as well. As we started to look into that, we just couldn’t quite get the resolution of data that you need to image or measure things like temperature and pressure. There are some various high-temperature electronics that have been developed—silicon carbide and gallium systems—that do operate at high temperatures. The problem is that they’re at a really low level of integration. So what that means is that you can’t do traditional electrical systems with them, and you can’t do anything close to what would be required for a rover. So our idea is to built a mobility platform that would be able to locomote, seeing new places and operating for a lot longer than you could with the systems that currently exist.

The primary goal is to first design our locomotion architecture to be as robust as possible. And then the second goal is to use as many simple, distributed, reactive mechanisms as we can to sort of guide the rover as it works its way across the surface of Venus.

How the heck are they going to lubricate a clockwork rover in those temperatures. The metal expansion factor alone could cause it to sieze up.

Glen,

Though there are obviously many challenges, mechanical engineers
have had multiple decades of experience in designing moving machinery
that operates at very high temperatures.

Case in point, the jet engine turbine, where the compressor raises the
air temperature to as much as 550C even before it has reached the
turbine blades, then the combustion process raises it again to as much
as 1590C in some engines. Beyond the melting point of many materials
and despite the fact that the turbine blades are subjected to enormous
centrifugal forces.

So one has to draw upon materials such as platinum (melting point 1768C)
with low coefficients of expansion.

But even that is only the start of the many challenges for the prospective
designer.

Gday Gary
Mech eng hat on :-)
Even a jet engine can export its lubricating oil to an external cooler.
If there is no external cool area, it becomes a lot more problematic.

Hi Andrew,

Indeed!

However, the real point I was trying to make, as the investigators
discuss, is that there are a range of materials such as platinum that have
low coefficients of expansion that can be used in high temperature
environments such as on the surface of Venus.

In many simple machines, the tribological interaction of their moving parts
does not necessitate the use of any lubricant at all. When was the last time
you saw someone bothering to oil or cool a mouse trap?

And in the first para i saw
I suspect he is being a bit over enthusiastic with that bit :-) ?????

Consider the use of ship-to-ship communications using semaphores.
The signalmen communicate mechanically by simply waving flags.

One of the phase I proposals (see section 4.5.3 of the Phase I report)
brainstorms the use of an orbiter bouncing RADAR off reflective
targets on the lander. The targets consist of spinning disks which have
an RF transparent window. The RADAR could ascertain the spin rates
and the authors suggest one approach where up to 32 variables a day
of telemetry could be communicated from an alphabet of tens of
millions of symbols.

When was the last time you saw someone bothering to oil or cool a mouse trap?

Never, but that level of mousetrap cant tell me how its feeling either :-)

Quote:

Consider the use of ship-to-ship communications using semaphores.

You must be psychic :-) as i had actually written about that method as a "tongue in cheek" reply as to how to do "mechanical" comms, but something in the probe has to know what to send and something has to drive the semaphore mechanism ( and that wont be by clockwork )

Quote:

brainstorms the use of an orbiter bouncing RADAR off reflective
targets on the lander.

Again, that requires some form of electronics feedback loop on the lander to control the spin rates, and if the electronics involved can do that, i assume they could do std comms.
Again, all good fun to theorise, but if its too hot for std electronics, i cant see how purely mechanical can replace it ( as much as i luv the idea )

Case in point, the jet engine turbine, where the compressor raises the
air temperature to as much as 550C even before it has reached the
turbine blades, then the combustion process raises it again to as much
as 1590C in some engines. Beyond the melting point of many materials
and despite the fact that the turbine blades are subjected to enormous
centrifugal forces.

When this goes wrong it goes badly wrong.

In 2010, an oil tube went leaking aboard a Qantas A380 (QF32)just left off Singapore on the way to Sydney.
This resulted in a breakage of a turbo fan which shrapnel flew through the wing and cut all wiring for the communication between avionics and engine. The Qantas control center in Sydney got a long stream of unexplainable error messages.

The captain finally succeeded to turn back to Singapore and land it safely, but it almost crash-landed with over 400 victims.

I agree that in a catastrophic fail mode, anything can go pearshaped very quickly, but i think we are still looking at the steady state design problems first ( which are quite extreme in this case ).
I like radar as it cant be affected as badly as optical would be by the atmoshpherics. ( Imagine trying to image mechanical semaphores ), but it still needs a motor etc to control it.

I reckon what they need is a fax machine on the orbiter and a hellschreiber unit on the lander.
Loss of bits of data becomes a no issue .

Again, that requires some form of electronics feedback loop on the lander to control the spin rates, and if the electronics involved can do that, i assume they could do std comms.
Again, all good fun to theorise, but if its too hot for std electronics, i cant see how purely mechanical can replace it ( as much as i luv the idea )

Andrew

Hi Andrew,

As the investigators discuss in the paper, the preferred solution for
communication is a transceiver built of high temperature electronics.

However, though transistors have been fabricated using materials such
as gallium nitride that can withstand the temperatures of Venus, no one
has yet built an entire transceiver from them.

Maybe soon.

But imagine a hypothetical of where active electronics was not available
at all.

There is an entire universe of passive electrical components, electromagnets,
relays, motors and purely mechanical devices from which a talented
engineering team could draw upon.

And don't forget that there was a world of sophisticated devices before the
invention of electronics and even before the practical application of electricity.

Built around 1770 and purely mechanical, he predates the invention
of the voltaic pile - the first battery - by Alessandro Volta in 1800.

Today, motors have already been fabricated using high temperature magnetic
wire, ceramics, stainless steel and so on, purposely designed to withstand
the Venus environment.

Ideally their control systems would be high temperature electronics.

But pushed, one could always call upon the fundamentals - resistance,
capacitance, inductance, reactance, reluctance - to build passive circuits
capable of systems and control, timing, measurement and so on. Throw
in electromagnetics and you have computational and memory storage
as well.

I recollect after a year of electrical engineering System's and Control
not seeing a single circuit element drawn. It was all math.
The fundamentals are such that the governing elements could have
been pneumatic or hydraulic or electrical but the mathematics and
analysis remained the same.

And of course you have people like Watt designing his first centrifugal
governor - a servomechanism - for use on a steam engine in 1788.
Though Laplace developed the Laplace transform around 1785 -
part of the mathematics that often powers modern systems and control
theory - I imagine Watt built his servosystems totally ignorant of it.

Fully agree.
My only contention has been with the "no electronics" bit.
I marvel at the range of mechanical inventions over time, but have a hard time imagining how they would work in a probe being sent to venus etc :-)
Babbage had the mechanical calculator, and the recent exploration of the antikythera capabilities show how advanced people were, but they all still required humans to drive them and analyse the results.
When it comes to remotely getting and sending data from a myriad of sensors i dont see it happening without some form of electronics, and if that exists, then i again cant see why std comms wouldnt be the result.
( But then again, i find it hard to keep up with all the advances being made in engineering, mechanical sciences, electronics etc )
Again, all fascinating stuff